Blog 10--Concept Map- Adding and subtracting fractions with unlike denominators

Adding and Subtracting Fractions with unlike denominators

CCSS.Math.Content.5.NF.A.1 Add and subtract fractions with unlike denominators (including mixed numbers) by replacing given fractions with equivalent fractions in such a way as to produce an equivalent sum or difference of fractions with like denominators. For example, 2/3 + 5/4 = 8/12 + 15/12 = 23/12. (In general, a/b + c/d = (ad + bc)/bd.)

I.       Vocabulary

Having vocabulary words for adding and subtracting fractions is absolutely the most important. The class will have about 10 vocabulary words that they will have to define and actually know so that they will be able to use and understand them in the lesson. The student will have to learn how to add and subtract fractions with unlike denominators, and will have to work out different word problems that use terms such as "find the sum" or "find the equivalent."

A.    Define as a class

Common Denominator
Multiple
Common Multiple
Factor
Numerator
Denominator
Sum
Difference
Equivalent
Fraction

B.    Crossword Puzzle for ending bell activity

II.     Fraction Strips

Fraction strips, to me, are the easiest way to learn how to add and subtract fractions with unlike denominators. The easiest way to use them is to use cut outs, and you will simply place them on top of each other to see exactly what fraction you end up with. This helps students because it is more hands on, and has a visual effect for the students.

A.    Show equivalents

1.    Interactive Website

B.        Have cut out fraction strips to take home and practice with

III.    Number Line

The number line is more difficult than the rest of the options. Using this method, I would have to had focused a lot on making equivalent fractions. This method is easier if you have mastered reducing fractions and finding equivalents because if you can find equivalents by using the Least Common Denominator, then you just simply add the numerators using a number line. This is more effective for using normal fractions rather than mixed numbered fractions.

A.    Make a number line with tape on the floor and have students walk to add and subtract

B.    Create their own number line on a poster and have laminated, taped objects for them to add and subtract on their own

IV.    Least Common Denominator

This method is what is most commonly used when adding and subtracting fractions with unlike denominators. The student will find the common denominator by finding the factors of the denominators and determining which number they have in common.. The student will eventually have a simple addition problem, and all they would have to do is simplify at the end.

A.    Complete Trail Mix Activity as a class using LCD

I would have ingredients for Trail Mix such as Raisins, M&M's, Chex Cereal, Cheerios, Pretzels, and I would have the ingredients listed such as 3/4+7/8=___cup of M&M's.

B.    Calculate LCD using Pizza Worksheet

V.     Fruit Shoot Fraction Addition

Using games, to me, is a very effective way to get students to practice. Using this game in the class allows the student to gain access with technology by using the Smart Board that I will have in my classroom. The game is played by a random addition problem pops up and you have to shoot the correct addition problem to move on to the next level.

A.    Use Website in a center

B.    Have a student demonstrate how to play the game using Smart Board